Molybdenum and tungsten complexes of the neutral tripod ligands HC(pz) 3 and MeC(CH 2PPh 2) 3

Abstract

Starting from [M(CO) 6], seven-coordinated complexes of tungsten and molybdenum containing the facially coordinating ligands HC(pz) 3 ( 1) and MeC(CH 2PPh 2) 3 ( 2) were obtained in a two-step reaction sequence. The complexes have a 4:3 piano stool geometry with almost perfect C S symmetry in the crystal. In solution, they show the typical fluxional behavior for seven-coordinated complexes even at low temperature. Complete oxidative decarbonylation occurs when [HC(pz) 3Mo(CO) 3] ( 4) or [MeC(CH 2PPh 2) 3Mo(CO) 3] ( 6) are treated with an excess of I 2 or Br 2.